Low-cost photolithography system for cell biology labs

Abstract

Soft lithography, a tool widely applied in biology and life sciences with numerous applications, uses the soft molding of photolithography-generated master structures by polymers. The central part of a photolithography set-up is a mask-aligner mostly based on a high-pressure mercury lamp as an ultraviolet (UV) light source. This type of light source requires a high level of maintenance and shows a decreasing intensity over its lifetime, influencing the lithography outcome. In this paper, we present a low-cost, bench-top photolithography tool based on ninety-eight 375 nm light-emitting diodes (LEDs). With approx. 10 W, our presented lithography set-up requires only a fraction of the energy of a conventional lamp, the LEDs have a guaranteed lifetime of 1000 h, which becomes noticeable by at least 2.5 to 15 times more exposure cycles compared to a standard light source and with costs less than 850 C it is very affordable. Such a set-up is not only attractive to small academic and industrial fabrication facilities who want to enable work with the technology of photolithography and cannot afford a conventional set-up, but also microfluidic teaching laboratories and microfluidic research and development laboratories, in general, could benefit from this cost-effective alternative. With our self-built photolithography system, we were able to produce structures from 6 μm to 50 μm in height and 10 μm to 200 μm in width. As an optional feature, we present a scaled-down laminar flow hood to enable a dust-free working environment for the photolithography process.

Accessible, large-area, uniform dose photolithography using a moving light source

“…As the MOLIS system uses an inexpensive stepper-motor based 3D printer (∼$150) to position a battery-powered UV-LED flashlight (∼$50) as the illumination head, construction cost only ∼$200 in materials. For reference, previously documented photolithography platforms designed to have notably low construction require ∼$1000 in materials cost [1,20,21]. This low cost of construction makes the proposed MOLIS system particularly appealing not only for labs which frequently utilize photolithographic microfabrication and want to explore additional customizability, but also for research labs operating in resource-limited environments or looking to develop occasional microfabricated systems without a large upfront investment in equipment and infrastructure.…”